title: Increased invasion and tumorigenicity capacity of CD44+/CD24- breast cancer MCF7 cells in vitro and in nude mice.
abstract: BACKGROUND
  Identification of cancer stem cells (CSCs) and their behaviors will provide insightful information for the future control of human cancers. This study investigated CD44 and CD24 cell surface markers as breast cancer CSC markers in vitro and in vivo.
  
  
  METHODS
  Flow cytometry with CD44 and CD24 markers was used to sort breast cancer MCF7 cells for scanning electron microscopy (SEM), tumor cell invasion assay, and nude mouse xenograft assay.
  
  
  RESULTS
  Flow cytometry assay using CD44 and CD24 markers sorted MCF7 cells into four subsets, i.e., CD44+/CD24-/low, CD44-/CD24+, CD44+/CD24+, and CD44-/CD24-. The SEM data showed that there were many protrusions on the surface of CD44+/CD24-/low cells. CD44+/CD24-/low cells had many microvilli and pseudopodia. The CD44+/CD24-/low cells had a higher migration and invasion abilities than that of the other three subsets of the cells. The in vivo tumor formation assay revealed that CD44+/CD24- cells had the highest tumorigenic capacity compared to the other three subsets.
  
  
  CONCLUSIONS
  CD44 and CD24 could be useful markers for identification of breast CSCs because CD44+/CD24-/low cells had unique surface ultrastructures and the highest tumorigenicity and invasive abilities.
authors.affiliation: Department of Radiotherapy, Second Affiliated Hospital of Jilin University, 130021, Changchun, China. chinawtj218@163.com.
authors.forename: Wenxing
authors.initials: W
authors.lastname: Yan
authors.forename: Yubing
authors.initials: Y
authors.lastname: Chen
authors.forename: Yueliang
authors.initials: Y
authors.lastname: Yao
authors.forename: Hongmei
authors.initials: H
authors.lastname: Zhang
authors.forename: Tiejun
authors.initials: T
authors.lastname: Wang